1: /*
2: * Copyright (C) 1999-2001, 2008, 2016 Free Software Foundation, Inc.
3: * This file is part of the GNU LIBICONV Library.
4: *
5: * The GNU LIBICONV Library is free software; you can redistribute it
6: * and/or modify it under the terms of the GNU Library General Public
7: * License as published by the Free Software Foundation; either version 2
8: * of the License, or (at your option) any later version.
9: *
10: * The GNU LIBICONV Library is distributed in the hope that it will be
11: * useful, but WITHOUT ANY WARRANTY; without even the implied warranty of
12: * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
13: * Library General Public License for more details.
14: *
15: * You should have received a copy of the GNU Library General Public
16: * License along with the GNU LIBICONV Library; see the file COPYING.LIB.
17: * If not, see <https://www.gnu.org/licenses/>.
18: */
19:
20: /*
21: * UTF-7
22: */
23:
24: /* Specification: RFC 2152 (and old RFC 1641, RFC 1642) */
25: /* The original Base64 encoding is defined in RFC 2045. */
26:
27: /* Set of direct characters:
28: * A-Z a-z 0-9 ' ( ) , - . / : ? space tab lf cr
29: */
30: static const unsigned char direct_tab[128/8] = {
31: 0x00, 0x26, 0x00, 0x00, 0x81, 0xf3, 0xff, 0x87,
32: 0xfe, 0xff, 0xff, 0x07, 0xfe, 0xff, 0xff, 0x07,
33: };
34: #define isdirect(ch) ((ch) < 128 && ((direct_tab[(ch)>>3] >> (ch & 7)) & 1))
35:
36: /* Set of direct and optional direct characters:
37: * A-Z a-z 0-9 ' ( ) , - . / : ? space tab lf cr
38: * ! " # $ % & * ; < = > @ [ ] ^ _ ` { | }
39: */
40: static const unsigned char xdirect_tab[128/8] = {
41: 0x00, 0x26, 0x00, 0x00, 0xff, 0xf7, 0xff, 0xff,
42: 0xff, 0xff, 0xff, 0xef, 0xff, 0xff, 0xff, 0x3f,
43: };
44: #define isxdirect(ch) ((ch) < 128 && ((xdirect_tab[(ch)>>3] >> (ch & 7)) & 1))
45:
46: /* Set of base64 characters, extended:
47: * A-Z a-z 0-9 + / -
48: */
49: static const unsigned char xbase64_tab[128/8] = {
50: 0x00, 0x00, 0x00, 0x00, 0x00, 0xa8, 0xff, 0x03,
51: 0xfe, 0xff, 0xff, 0x07, 0xfe, 0xff, 0xff, 0x07,
52: };
53: #define isxbase64(ch) ((ch) < 128 && ((xbase64_tab[(ch)>>3] >> (ch & 7)) & 1))
54:
55: /*
56: * The state is structured as follows:
57: * bit 1..0: shift
58: * bit 7..2: data
59: * Precise meaning:
60: * shift data
61: * 0 0 not inside base64 encoding
62: * 1 0 inside base64, no pending bits
63: * 2 XXXX00 inside base64, 4 bits remain from 2nd byte
64: * 3 XX0000 inside base64, 2 bits remain from 3rd byte
65: */
66:
67: static int
68: utf7_mbtowc (conv_t conv, ucs4_t *pwc, const unsigned char *s, size_t n)
69: {
70: state_t state = conv->istate;
71: int count = 0; /* number of input bytes already read */
72: if (state & 3)
73: goto active;
74: else
75: goto inactive;
76:
77: inactive:
78: {
79: /* Here (state & 3) == 0 */
80: if (n < count+1)
81: goto none;
82: {
83: unsigned char c = *s;
84: if (isxdirect(c)) {
85: *pwc = (ucs4_t) c;
86: conv->istate = state;
87: return count+1;
88: }
89: if (c == '+') {
90: if (n < count+2)
91: goto none;
92: if (s[1] == '-') {
93: *pwc = (ucs4_t) '+';
94: conv->istate = state;
95: return count+2;
96: }
97: s++; count++;
98: state = 1;
99: goto active;
100: }
101: goto ilseq;
102: }
103: }
104:
105: active:
106: {
107: /* base64 encoding active */
108: unsigned int wc = 0;
109: state_t base64state = state;
110: unsigned int kmax = 2; /* number of payload bytes to read */
111: unsigned int k = 0; /* number of payload bytes already read */
112: unsigned int base64count = 0; /* number of base64 bytes already read */
113: for (;;) {
114: unsigned char c = *s;
115: unsigned int i;
116: if (c >= 'A' && c <= 'Z')
117: i = c-'A';
118: else if (c >= 'a' && c <= 'z')
119: i = c-'a'+26;
120: else if (c >= '0' && c <= '9')
121: i = c-'0'+52;
122: else if (c == '+')
123: i = 62;
124: else if (c == '/')
125: i = 63;
126: else {
127: /* c terminates base64 encoding */
128: if (base64state & -4)
129: goto ilseq; /* data must be 0, otherwise illegal */
130: if (base64count)
131: goto ilseq; /* partial UTF-16 characters are invalid */
132: if (c == '-') {
133: s++; count++;
134: }
135: state = 0;
136: goto inactive;
137: }
138: s++; base64count++;
139: /* read 6 bits: 0 <= i < 64 */
140: switch (base64state & 3) {
141: case 1: /* inside base64, no pending bits */
142: base64state = (i << 2) | 0; break;
143: case 0: /* inside base64, 6 bits remain from 1st byte */
144: wc = (wc << 8) | (base64state & -4) | (i >> 4); k++;
145: base64state = ((i & 15) << 4) | 2; break;
146: case 2: /* inside base64, 4 bits remain from 2nd byte */
147: wc = (wc << 8) | (base64state & -4) | (i >> 2); k++;
148: base64state = ((i & 3) << 6) | 3; break;
149: case 3: /* inside base64, 2 bits remain from 3rd byte */
150: wc = (wc << 8) | (base64state & -4) | i; k++;
151: base64state = 1; break;
152: }
153: if (k == kmax) {
154: /* UTF-16: When we see a High Surrogate, we must also decode
155: the following Low Surrogate. */
156: if (kmax == 2 && (wc >= 0xd800 && wc < 0xdc00))
157: kmax = 4;
158: else
159: break;
160: }
161: if (n < count+base64count+1)
162: goto none;
163: }
164: /* Here k = kmax > 0, hence base64count > 0. */
165: if ((base64state & 3) == 0) abort();
166: if (kmax == 4) {
167: ucs4_t wc1 = wc >> 16;
168: ucs4_t wc2 = wc & 0xffff;
169: if (!(wc1 >= 0xd800 && wc1 < 0xdc00)) abort();
170: if (!(wc2 >= 0xdc00 && wc2 < 0xe000)) goto ilseq;
171: *pwc = 0x10000 + ((wc1 - 0xd800) << 10) + (wc2 - 0xdc00);
172: } else {
173: *pwc = wc;
174: }
175: conv->istate = base64state;
176: return count+base64count;
177: }
178:
179: none:
180: conv->istate = state;
181: return RET_TOOFEW(count);
182:
183: ilseq:
184: conv->istate = state;
185: return RET_SHIFT_ILSEQ(count);
186: }
187:
188: /*
189: * The state is structured as follows:
190: * bit 1..0: shift
191: * bit 7..2: data
192: * Precise meaning:
193: * shift data
194: * 0 0 not inside base64 encoding
195: * 1 0 inside base64, no pending bits
196: * 2 XX00 inside base64, 2 bits known for 2nd byte
197: * 3 XXXX inside base64, 4 bits known for 3rd byte
198: */
199:
200: /* Define this to 1 if you want the so-called "optional direct" characters
201: ! " # $ % & * ; < = > @ [ ] ^ _ ` { | }
202: to be encoded. Define to 0 if you want them to be passed straight through,
203: like the so-called "direct" characters.
204: We set this to 1 because it's safer.
205: */
206: #define UTF7_ENCODE_OPTIONAL_CHARS 1
207:
208: static int
209: utf7_wctomb (conv_t conv, unsigned char *r, ucs4_t iwc, size_t n)
210: {
211: state_t state = conv->ostate;
212: unsigned int wc = iwc;
213: int count = 0;
214: if (state & 3)
215: goto active;
216:
217: /*inactive:*/
218: {
219: if (UTF7_ENCODE_OPTIONAL_CHARS ? isdirect(wc) : isxdirect(wc)) {
220: r[0] = (unsigned char) wc;
221: /*conv->ostate = state;*/
222: return 1;
223: } else {
224: *r++ = '+';
225: if (wc == '+') {
226: if (n < 2)
227: return RET_TOOSMALL;
228: *r = '-';
229: /*conv->ostate = state;*/
230: return 2;
231: }
232: count = 1;
233: state = 1;
234: goto active;
235: }
236: }
237:
238: active:
239: {
240: /* base64 encoding active */
241: if (UTF7_ENCODE_OPTIONAL_CHARS ? isdirect(wc) : isxdirect(wc)) {
242: /* deactivate base64 encoding */
243: count += ((state & 3) >= 2 ? 1 : 0) + (isxbase64(wc) ? 1 : 0) + 1;
244: if (n < count)
245: return RET_TOOSMALL;
246: if ((state & 3) >= 2) {
247: unsigned int i = state & -4;
248: unsigned char c;
249: if (i < 26)
250: c = i+'A';
251: else if (i < 52)
252: c = i-26+'a';
253: else if (i < 62)
254: c = i-52+'0';
255: else if (i == 62)
256: c = '+';
257: else if (i == 63)
258: c = '/';
259: else
260: abort();
261: *r++ = c;
262: }
263: if (isxbase64(wc))
264: *r++ = '-';
265: state = 0;
266: *r++ = (unsigned char) wc;
267: conv->ostate = state;
268: return count;
269: } else {
270: unsigned int k; /* number of payload bytes to write */
271: if (wc < 0x10000) {
272: k = 2;
273: count += ((state & 3) >= 2 ? 3 : 2);
274: } else if (wc < 0x110000) {
275: unsigned int wc1 = 0xd800 + ((wc - 0x10000) >> 10);
276: unsigned int wc2 = 0xdc00 + ((wc - 0x10000) & 0x3ff);
277: wc = (wc1 << 16) | wc2;
278: k = 4;
279: count += ((state & 3) >= 3 ? 6 : 5);
280: } else
281: return RET_ILUNI;
282: if (n < count)
283: return RET_TOOSMALL;
284: for (;;) {
285: unsigned int i;
286: unsigned char c;
287: switch (state & 3) {
288: case 0: /* inside base64, 6 bits known for 4th byte */
289: c = (state & -4) >> 2; state = 1; break;
290: case 1: /* inside base64, no pending bits */
291: i = (wc >> (8 * --k)) & 0xff;
292: c = i >> 2; state = ((i & 3) << 4) | 2; break;
293: case 2: /* inside base64, 2 bits known for 2nd byte */
294: i = (wc >> (8 * --k)) & 0xff;
295: c = (state & -4) | (i >> 4); state = ((i & 15) << 2) | 3; break;
296: case 3: /* inside base64, 4 bits known for 3rd byte */
297: i = (wc >> (8 * --k)) & 0xff;
298: c = (state & -4) | (i >> 6); state = ((i & 63) << 2) | 0; break;
299: default: abort(); /* stupid gcc */
300: }
301: if (c < 26)
302: c = c+'A';
303: else if (c < 52)
304: c = c-26+'a';
305: else if (c < 62)
306: c = c-52+'0';
307: else if (c == 62)
308: c = '+';
309: else if (c == 63)
310: c = '/';
311: else
312: abort();
313: *r++ = c;
314: if ((state & 3) && (k == 0))
315: break;
316: }
317: conv->ostate = state;
318: return count;
319: }
320: }
321: }
322:
323: static int
324: utf7_reset (conv_t conv, unsigned char *r, size_t n)
325: {
326: state_t state = conv->ostate;
327: if (state & 3) {
328: /* deactivate base64 encoding */
329: unsigned int count = ((state & 3) >= 2 ? 1 : 0) + 1;
330: if (n < count)
331: return RET_TOOSMALL;
332: if ((state & 3) >= 2) {
333: unsigned int i = state & -4;
334: unsigned char c;
335: if (i < 26)
336: c = i+'A';
337: else if (i < 52)
338: c = i-26+'a';
339: else if (i < 62)
340: c = i-52+'0';
341: else if (i == 62)
342: c = '+';
343: else if (i == 63)
344: c = '/';
345: else
346: abort();
347: *r++ = c;
348: }
349: *r++ = '-';
350: /* conv->ostate = 0; will be done by the caller */
351: return count;
352: } else
353: return 0;
354: }
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